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Field
Name
R/W
Description
7
LSBSEL
R/W
LSB First Transfer Select
0: First transmit the most significant bit (MSB)
1: First transmit the least significant bit (LSB)
8
ISSEL
R/W
Internal Slave Device Select
When CTRL1_SSEN=1 (software NSS mode), select internal NSS
level by configuring the bit
0: Internal NSS is low
1: Internal NSS is high
9
SSEN
R/W
Software Slave Device Enable
0: Software NSS mode is disabled, and the internal NSS level is
determined by external NSS pin
1: Software NSS mode is enabled, and the internal NSS level is
determined by external NSS pin
10
RXOMEN
R/W
Receive Only Mode Enable
0: Transmit and receive at the same time
1: Receive-only mode
RXOMEN bit and BMEN bit together determine the transmission
direction in the two-line and two-way mode. In the configuration of
multiple slave devices, in order to avoid data transmission collision, it is
necessary to set RXOMEN bit to 1 on the slave devices that are not
accessed.
11
DFLSEL
R/W
Data Frame Length Format Select
0: 8-bit data frame format
1: 16-bit data frame format
Only when SPIEN=0, can this bit be written to change the data frame
length.
12
CRCNXT
R/W
CRC Transfer Next Enable
0: The next transmitted data is from transmit buffer
1: The next transmitted data is from CRC register
Note: After the last data is written to SPI_DATA register, set CRCNXT
bit immediately.
13
CRCEN
R/W
CRC Calculate Enable
0: Disable
1: Enable
CRC check function only applies to full duplex mode; only when
SPIEN=0, can this bit be changed.
14
BMOEN
R/W
Bidirectional Mode Output Enable
0: Disable, namely, receive-only mode
1: Enable, namely, transmit-only mode
When BMEN=1, namely, in single-line/double-line mode, this bit
decides the transmission direction of transmission line.
15
BMEN
R/W
Bidirectional Mode Enable
0: Double-line unidirectional mode
1: Single-line bidirectional mode
Single-line two-way transmission means: the transmission between
MOSI pin of data master and MISO pin of slave